Gasoline is a volatile flammable mixture of hydrocarbons mainly hexane, heptane and octane, obtained from petroleum and used as a solvent and a fuel for internal-combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives.
The characteristic of a particular gasoline blend to resist autoigniting, which causes knocking and reduces efficiency in reciprocating engines, is measured by its octane rating. Octane rating or octane number is a standard measure of the performance of an engine or aviation fuel. The higher the octane number, the more compression the fuel can withstand before igniting. Gasoline is produced in several grades of octane rating. Lead compounds are no longer used to regulate and increase octane-rating, but many other additives are put into gasoline to improve its chemical stability, control corrosiveness and determine performance characteristics under intended use.
Gasoline has conventionally been produced from crude oil of fossil origin. Demand for renewable/sustainable energy is vastly increasing. For example, the European Union requires renewable energy to have at least a 10% share of transport energy by 2020, and even higher shares are being attempted regionally.
For a renewable bio-based gasoline, efforts to date have been devoted mostly to ethanol. Other gasoline biocomponents similar to ethanol in terms of technical specifications for fuel include, for example, biobutanol and biomethanol and bioethers manufactured from it, such as methyl tert-butyl ether (MTBE). Although ethanol is the dominant liquid biofuel globally, technical restrictions limit its use in conventional gasoline cars to 10-15 v/v % (bio-energy 7-10%). The use of other alcohols and ethers as oxygenated fuels is limited by the same restrictions. Since current conventional cars will continue to take the major share of gasoline car fleets for at least the next 10-20 years, it is necessary to establish and assess biocomponent options for them.
Interesting gasoline biocomponents are produced from biomass feedstocks. Biomass can be converted to biohydrocarbons by thermochemical conversion routes which include processes in which solid, liquid or gaseous hydrocarbon-rich feedstock is gasified and catalytically conditioned to synthesis gas, which then can be further refined to higher value products such as gasoline and diesel. The generally recognized difficulty with biomass is the fact that it contains oxygen, unlike conventional hydrocarbon fuels, and historically has not been readily convertible into a form that can be easily integrated into existing hydrocarbon based infrastructure. The biological feed materials may often cause, for example, poisoning and clogging of the catalyst material used in the conventional fuel production processes. Moreover, existing steamcrackers are not designed to remove high amounts of carbonoxides that would result from the steamcracking of these biofeedstock.
Part of crude oil in the refineries producing fossil oil products from crude oil can be replaced with bio-based raw materials (the so-called “co-feed”) to manufacture biogasoline. Biogasoline produced using these methods has considerably higher energy content compared to alcohols and ethers and is suitable for use as such in the existing vehicle fleet without any technical engine restrictions.
WO2008114033 discloses a process for the formation of biogasoline by the fluid catalytic cracking (FCC) of bio-oils, in particular fish oils, in combination with mineral oil. In the process the cracking produces bio-naphtha and bio-liquefied petroleum gas (LPG). The obtained bio-LPG component is post treated by alkylating or catalytically polymerizing and then combined with bionaphtha to form biogasoline.
WO2014210150 discloses a method that includes co-processing of a liquid thermally produced from biomass with a petroleum fraction feedstock in the FCC or field upgrader operations. The liquid thermally produced from biomass was produced from rapid thermal processing of a wood residue feedstock in a commercial fast pyrolysis process and is consider as renewable fuel oil (RFO).
Several publications disclose a direct processing of biomass or other oxygenated carbonaceous feedstocks in a circulating fluid bed reactor using a catalyst as the solid circulating media in an effort to directly deoxygenate the biomass and produce transportation fuels or fuel blends, as well as other hydrocarbons. Although some hydrocarbon products were produced, the yields were unacceptably low, and there was a high yield of char or coke and by-product gas produced. Moreover, often when biocontent of the fuels or fuel blends is increased, the quality of the fuel decreases.
Despite a good progress in the biofuel field there exists a need for an efficient, simple and economic process which can produce high quality fuel, especially gasoline from a renewable feedstock in high yields and yet upgrading the product quality. There is also need for good quality biocomponents suitable for use in gasoline blending without decreasing quality of gasoline.